1. Field of the Invention
The present invention relates to an automatic engine stop and start apparatus for automatically stopping and starting an engine.
2. Description of Prior Art
When a driver of a car encounters a traffic jam due to a car accident or wait for traffic signal and is obliged to stop the car for a long time, he or she usually stops an engine and restarts the engine when the traffic jam has disappeared in order to avoid waste of fuel consumption due to long time idling operation of the car.
On the other hand, if the driver stops the engine each time he or she stops the car at a crosspoint in a town area to wait for the traffic signal, he or she has to restart the engine each time he or she starts the car. This is not only troublesome but also impedes rapid start of the car.
However, the stop time in the town area occupies a considerable portion of a total run time and hence the amount of exhaust gas exhausted and the amount of fuel consumed during the idling operation of the car cannot be neglected.
Accordingly, an automatic engine stop and start apparatus which automatically stops the engine under a predetermined condition such as the stop of the car at the crosspoint in the town area and restarts the engine in response to an ordinary start operation (step-on of a clatch pedal) has been developed.
In a prior art apparatus of this type, when the engine stop condition is met while the car is going up a slope and the engine is automatically stopped, a booster pressure of a brake is reduced resulting in the reduction of a braking force in spite of the necessity of the braking force.